In a rewritable or recordable optical disc medium such as CD-R/RW, DVD±R/RW, or DVD-RAM, a defect occurs at a part of the medium in some cases if the same disc is repeatedly used. The defect is caused by damage or scratches of the medium, adhesion of fingerprints or taint, or deterioration of a recording film. If recording is performed on the defect portion, data cannot be normally read. It is difficult to eliminate the occurrence of such a defect on the whole disc surface. Accordingly, there has been employed an alternative processing method in which data are not recorded at a sector portion where the defect has occurred, but alternative recording of the defect sector is performed at an alternative region (spare region) provided on the same optical disc.
In order to confirm whether or not data recording has been normally performed in the alternative processing method, a so-called verifying operation in which data of a recorded sector are reproduced to assess the number of errors is carried out. In the case where errors exceeding an acceptable value are detected, it is determined as a recording failure (occurrence of a defect), and an alternative process is performed.
As a technique relating to the above, Patent document 1 discloses a storing device aiming at a high speed of a writing operation of data by reducing the number of writing times of data for the alternative process. The storing device is configured in such a manner that there is provided data storage means for temporarily storing data when performing the alternative process for data to be written into a defect sector, the data are temporarily stored into the data storage means when performing the alternative process for the data to be written into the defect sector, and data of a plurality of sectors for which the alternative process is performed are stored into a spare sector region at a time.
Patent document 1: Japanese Patent Application Laid-Open No. H11-185390